Field of the Invention
Exemplary embodiments of the present invention relate to an engine control method and apparatus for determining whether an injector mounted in a vehicle engine fails; and, particularly, to an engine control method and apparatus capable of reducing an influence of an air compressor when determining whether an injector fails.
Description of Related Art
An internal combustion engine, which is the engine of a vehicle, generates power by burning a mixture of outside air and fuel in a combustion chamber, wherein the fuel is injected into the combustion chamber by an injector that controlled by an electronic control unit (hereinafter, referred to as an “ECU”). If the injector fails, the engine is not properly synchronized, in which case a desired driving force may not be obtained and vibration and start-off or no restarting may occur. Accordingly, it is very important to accurately determine whether or not the injector fails.
Meanwhile, in connection with methods of determining whether an injector malfunctions, Patent Document 1 discloses a method of measuring an angular velocity of a crankshaft in a state in which injectors are off in all cylinders of an engine, and uses a variation in angular velocity of the crankshaft for each cylinder and a difference in the variation between the cylinders. That is, when the difference in the variation of the angular velocity of the crankshaft between the cylinders is over a predetermined range, the injector is determined to fail.
Meanwhile, the vehicle includes an air compressor to generate compressed air that is used for a brake and a variety of air systems. The air compressor compresses and discharges air in such a manner that its piston reciprocates by power transmitted from a vehicle engine by engagement therewith. When the air compressor of the vehicle is driven, the load of the compressor is applied to the crankshaft in a certain angle section per revolution of the engine, thereby affecting the angular velocity of the crankshaft. Accordingly, the angular velocity is reduced in the cylinder corresponding to the associated angle section, and hence it may be erroneously recognized that the injector for the associated cylinder fails.